Technical Field
The embodiments relate generally to systems and methods for processing audio, and, more specifically, to systems and methods for processing audio for increased perceived loudness while retaining changes in perceived volume.
Background Art
Audio production can include the pre-recording processing, recording, mixing, and/or mastering of sound. These phases of audio production can all involve processing of audio, which includes the manipulation of the audio to produce an improved digital audio file.
During audio processing, a representation of audio can be manipulated (e.g., enhanced) as either a digital or analog signal. A digital signal (i.e., digital audio) comprises a series of ones and zeros that represent a sound wave (i.e., audio). An analog signal (i.e., analog audio) comprises a continuous electrical signal that represents the sound wave. Digital manipulation (i.e., modulation) involves processing the ones and zeros of the digital signal, such as via a processor executing a formula. Analog manipulation (i.e., modulation) involves passing the analog signal through one or more physical components, such a circuit containing resistors, capacitors, op amps, and/or a vacuum tube. Whereas an analog compressor is made up of physical components, a digital compressor can be a set of instructions executed by a processor, such as a plug-in that operates within a digital audio workstation (DAW).
Typically, the audio that needs processing is one or more digital audio files. For example, a user may select one or more .WAV files representing songs that need processing. While the audio processing may take place entirely in the digital domain, the digital audio is commonly converted to analog audio and manipulated with analog audio components in most commercial audio production environments. This is the case, in part, because of the pleasing audio qualities that analog components can add to the audio. However, in environments where cost is a factor, some or all of the audio production process may be carried out digitally through the use of plugins and software, some of which may attempt to model the characteristics of physical analog equipment.
For example, the recording process involves recording sound in the digital domain in the form of digital audio files. Often, some processing, such as pre-mixing, of these files will occur in order to add some clarity or change the levels of the recorded audio, and to determine whether additional takes are necessary.
Similarly, the mixing process can involve processing audio by raising or lowering levels for particular tracks, adding effects, adding equalization, adding compression, and so forth, in order to create a clearer sounding audio production.
As another example, the mastering process involves enhancing recorded audio from a source, such as a compact disc (CD) containing a final mix of the recorded audio, to create a master version of the audio with improved sound translation and increased loudness for the best possible playback on various sound systems. The enhancement almost always includes modifying the audio by applying some form of compression, limiting, and/or equalization to the audio.
The end goal of the mastering process is typically to create a master version of the enhanced audio that can be used to replicate and/or distribute the audio. For example, the master audio may be stored digitally on a compact disk. Alternatively, an analog version of the master audio may be stored on tape or vinyl. In either case, the medium holding the final audio is referred to as the “master,” and is generally used to replicate the audio, such as in the creation of vinyl, compact discs, digital files for download, or other music media for public use.
Mastering and mixing engineers and/or home users almost always need to apply corrective equalization and/or dynamics processing (e.g., compression and/or limiting) in order to improve upon sound translation on all playback systems and increase loudness. When processing audio, dynamics processing (e.g., dynamic compression or limiting) is used to increase the volume of the recorded audio to two or three times the original volume so that the volume level can be competitive with that of other music in the market for sale. Achieving competitive volume levels is important so that the mastered song is not perceived as quieter and/or less energetic than other songs played on a listener's sound system. However, this type of dynamic enhancement usually flattens the volume levels and dynamic changes in the audio, removing fluctuation in dynamics (loud parts vs. quiet parts) so that the listener is less able to distinguish volume changes in the music and the impact of dynamic instruments like drums. This type of compression and limiting is very common and the increases in levels can also cause audible distortion in the music.
Similar techniques are used, for example, to ensure that commercials are loud enough to stand out and catch the attention of viewers. Additionally, mixing engineers for television and movies process sounds, voices, music, etc. in order to achieve levels and clarity that is appropriate for the particular application.
In addition to audio professionals (e.g., mastering engineers, mixers, mixers for film (television and movie audio), audio engineers, audio producers, recording studio engineers, studio musicians, etc.), home enthusiasts and hobbyists may also be involved with various aspects of audio production. For example, some people record, mix, remix, master, and/or otherwise produce audio, such as music, as a hobby. Other people are stereo enthusiasts (e.g., audiophiles) who use hardware and/or software to process “finished” audio to achieve a better listening experience. Production of audio at nearly any level involves some form of audio processing. However, these hobbyists and at-home enthusiasts are often limited by their lack of training and the expense required to purchase professional-level equipment for achieving commercial-level loudness without destroying dynamics and/or introducing distortion.
Therefore, a need exists for systems and methods of processing audio that can achieve commercially competitive audio levels without destroying the dynamics (i.e., perceived volume changes) of the song or causing distortion in the audio.
Accordingly, systems and methods are provided herein for processing audio to bring the volume levels up to today's very loud digital levels (or louder) while reducing distortion and retaining more volume dynamics (i.e., perceived changes in volume) than prior systems have ever allowed in the past.